No, they aren't a "necessity". Most homes, if properly landscaped and
maintained, will do just fine without them.

Nonsense. That may be true in Arizona, but falling water from the eaves will
leave a trench around the house that nothing will grow in.

unless code in your jurisdiction _requires_ gutters
(which is highly unlikely), you do not have grounds to break
your contract.

Not so unlikely. Our midwest community requires gutters on new housing per the
new BOCA codes. Other areas have required gutters in public and commercial
buildings for many years. Did you notice the ones on your church this morning?
Cheers

Joe